Biofuels offer an alternative to petroleum products for liquid fuel? There's the question of economies of scale. One person may make and use his own biodiesel. Maybe a thousand people in a city. But millions of vehicles? It is not simply a question of the cost of a 40 gallon batch. How about a million gallons? Even a million gallons wouldn't last long. Then there's the billion Chinese to consider who want the cooking oil for domestic use, rather than selfish Americans diverting food products to power their capitalistic little diesel cars and trucks. Marxism would dictate that for the benefit of the workers and politicians, government would seize stockpiles of veggie oil, for redistribution to McDonalds employees.

Since centuries vegetable oils are consumed as human food but it also finds applications in biodiesel production which is attracting more attention. But due to being in competition with food it could not be sustainable and leads the need to search for alternative. Nowdays microbes-derived oils (single cell oils) seem to be alternatives for biodiesel production due to their similar composition to that of vegetable oils. However, the cold flow properties of the biodiesel produced from microbial oils are unacceptable and have to be modified by an efficient transesterification. Glycerol which is by product of transesterification can be valorised into some more useful products so that it can also be utilised along with biodiesel to simplify the downstream processing. The review paper discusses about various potent microorganisms for biodiesel production, enzymes involved in the lipid accumulation, lipid quantification methods, catalysts used in transesterification (including enzymatic catalyst) and valorisation of glycerol.

Nearly all of the biofuels problems relate to ethanol not biodiesel. The myoptic media likes to lump them together for their dumbed-down audience.

At the farmstead scale, Fuelfarmer has shown biodiesel can be successfully done in Virginia with a small percent of cropland, comparable to what one would set aside for feeding draft animals traditionally.

Big oilcrop producers find they can get a high value food oil product and biodiesel can be made from the 'waste' and substandard crop percent.

It's not feasible to replace any significant portion of the diesel fuel market with biodiesel, however enough can be produced to be used as a fuel additive for all petro-diesel to make it burn cleaner and reduce toxic pollution